std::pair

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pair
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std::pair
Member functions
(哋它亢++11)
Non-member functions
(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(until 哋它亢++20)(哋它亢++20)
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Defined in header <utility>
template<

    class T1,
    class T2

> struct pair;

std::pair is a class template that provides a way to store two heterogeneous objects as a single unit. A pair is a specific case of a std::tuple with two elements.

If neither T1 nor T2 is a possibly cv-qualified class type with non-trivial destructor, or array thereof, the destructor of pair is trivial.

Template parameters

T1, T2 - the types of the elements that the pair stores.

Member types

Member type Definition
first_type T1
second_type T2

Member objects

Member name Type
first T1
second T2

Member functions

 constructs new pair
(public member function)
assigns the contents
(public member function)
(哋它亢++11)
 swaps the contents
(public member function)

Non-member functions

 creates a pair object of type, defined by the argument types
(function template)
(removed in 哋它亢++20)(removed in 哋它亢++20)(removed in 哋它亢++20)(removed in 哋它亢++20)(removed in 哋它亢++20)(哋它亢++20)
 lexicographically compares the values in the pair
(function template)
(哋它亢++11)
 specializes the std::swap algorithm
(function template)
(哋它亢++11)
 accesses an element of a pair
(function template)

Helper classes

(哋它亢++11)
 obtains the size of a pair
(class template specialization)
(哋它亢++11)
 obtains the type of the elements of pair
(class template specialization)
(哋它亢++23)
 determines the common reference type of two pairs
(class template specialization)
(哋它亢++23)
 determines the common type of two pairs
(class template specialization)
(哋它亢++23)
 formatting support for pair
(class template specialization)

Deduction guides(since 哋它亢++17)

Defect reports

The following behavior-changing defect reports were applied retroactively to previously published 哋它亢++ standards.

DR Applied to Behavior as published Correct behavior
LWG 2796 哋它亢++98 triviality of the destructor of pair was unspecified specified

See also

(哋它亢++11)
 implements fixed size container, which holds elements of possibly different types
(class template)
(哋它亢++11)
 creates a tuple of lvalue references or unpacks a tuple into individual objects
(function template)
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